Roasting and smelting furnace



Oct. 371, 1939. w JAEGER 2,177,654

ROASTING- AND SMELTING FURNACE Filed March l5, 1937 5 Sheets-Sheet l 757 56 2e 55 26+ bff 2e-68`\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ l /l -.67 4# fw 26'g- 53 22 2.5 9 621 1 2o 2 26 .20 2/ 23 /////////%9 f m4 y '7 f5 f8..w/- mi Jian.: M//zr/Evgyef ,6 l ATTORNES Oct. 31, 1939. Hi w. JAEGER2,177,654

ROASTING AND SMELTING FURNACE Filed March 15, 1937 s sheets-sheet sATTORNEY Patented Oct. 31, 1939 PATENT OFFICE ROASTING AND SMELTINGFURNACE Hans William Jaeger,

of one-half to Fred B.

Application March 15,

3 Claims.

This invention relates to roasting and smelting .furnaces of thereverberatory type and the primary object of this invention is toprovide a furnace of this nature in which the roasting and smelting ofores is carried out in one continuous process.

Another object of the invention is to provi-de a continuous processroasting and smelting furnace of this type which is adapted to beconstructed in comparatively small sizes thus making said furnacesavailable for use in smaller mining operations and making it especiallydesirable for use in mines which have poor transportation facilities andwhich are located at great distances from smelters,

j Another object of the invention is to provide a continuous processroasting and smelting furnace having three separately constructedsections providing an upper roasting chamber, a lower smelting chamberand a temperature control chamber positioned between the roasting andsmelting chambers.

Another object of the invention is to provide a continuous processreverberatory roasting and v25 smelting furnace which is adapted foreither low grade or complex ores, which is simple in construction andeiiicient in operation and which makes possible a substantial saving intransportation and smelter costs.

Another object of this invention is to provide a combined roasting andsmelting furnace of this nature having means which collects and retainssubstantially all dust and substantially al1 zinc and arsenic and likesubstances which are 35 yvolatilized during the smelting process andwhich would otherwise pass out through the stack.

Another object is to provide a continuous process roasting and smeltingfurnace which uses less flux than is ordinarily used in the smelting ofores and which does not require any flux at all in the smelting of someores.

Other objects are to provide a continuous process roasting and smeltingfurnace which saves in fuel due to the fact that it employs ahydrocarbon burner, which saves in the time of roasting and smelting, asthe furnace can be tapped at more frequent intervals than the ordinarysmelter furnace, which saves in the cost of labor required in connectionwith the roasting and smelting of ore and which obtains a higherpercentage of recovery from the ores due to the maintaining of a morecomplete and even fluidity which results in a cleaner and more completeseparation.

Other and more specific objects of the invention will be apparent fromthe following description taken in connection with the accompanyingdrawings.

In the drawings Fig. 1 is a longitudinal vertical section of acontinuous process ore roaster Seattle, Wash., assignor Dawley, Seattle,Wash.

1937, Serial No. 130,811

(Cl. 26S- 10) and smelter constructed in accordance with this invention.

Fig. 2 is a transverse vertical section of the same, taken substantiallyon a broken line 2-2 of Fig. 1.

Fig. 3 is a horizontal section substantially on broken line 3-3 of Fig.1.

Fig. 4 is a diagrammatic view of one form of driving means that may beused with the invention.

Like reference numerals designate like parts throughout the severalviews.

The continuous process roasting and smelting furnace shown in thedrawings is made up of a lower ore smelting section I0, a medialtemperature adjusting section I I, and an upper ore roasting section I2.The lower section IU comprises a smelting chamber I3 surrounded by wallsI4 of heat resistant material, as iirebrick, and having a floor portionI5 preferably of silica sand. The entire structure may rest on a base I6of concrete. Suitable openings I1 and I8 may be provided in the walls I4of the lower section for tapping the same to draw off the slag andmatte.

A hydrocarbon burner I9 extends into one end or into any other suitableportion of the smelting chamber I3 above the level which material willnormally be maintained therein. The top of the smelting chamber I3 isformed by arches 2D of heat resistant masonry. These arches 20 haveupwardly protruding portions 2I which intert telescopically withdownwardly protruding portions 22 of the medial section II and formexpansion joints between these two furnace sections. An uprightpassageway 23 connects the end portion of the smelting chamber remotefrom the hydrocarbon burner with a horizontal temperature adjustingchamber or passageway 24 in the medial section II. An inclined ore inletpassageway 25 communicatively connects the smelting chamber I3 with themedial section I I near the end at which the hydrocarbon burner I9 ispositioned. The incline-d passageway 25 allows roasted ore to pass fromthe upper chambers into the smelting chamber I3.

The medial temperature adjusting section II and upper smelting sectionI2 are each supported on transverse metal beams 26 and said beams 26 aresupported by a steel frame work 21 provided on the exterior of theroasting and smelting furnace. This means of support makes it possibleto construct the three sections IIJ, II and I2 independently of eachother and to provide successful expansion joints therebetween.

A roasting chamber 28 is provided in the upper furnace section I2 and anendless driven ore conveyor is provided in said roasting chamber. Thisendless driven ore conveyor comprises a plurality of links 29 operableon sprocket wheels 30. The sprocket wheels 38 are mounted on transverseshafts 3i and 32 which are journaled in bearings 33 positioned in thewalls or external to the walls of the upper furnace section I2.Preferably both of the shafts Si and 32 are driven as by link belts 34operating on sprocket wheel means 35 on said shafts and connected withsprocket pinion means 36 of transmission 3l. The sprocket pinion means36 is connected by worm wheel 38, worm 39, bevel gears 40, sprocketwheel 4|, link belt 42 with a driving means as a motor 43 whichpreferably provides at least three different driving speeds. The abovedescribe-d driving means provides for driving the ore conveyor at veryslow speed and for applying the driving power at both ends of the same.

When necessary, especially in connection with relatively long conveyors,driving force may be applied at one or more locations between the twoends.

The links 29 of the conveyor are preferably in the form of speciallyconstructed flat plates articulated together and extending substantiallyacross the roasting chamber to form an endless traveling apron on whichthe ore may rest during the roasting process. These plate like linkmembers 29 preferably rest upon track members 45 on the walls of thefurnace as shown in Fig. 2. Preferably the shafts 3l and 32 are hollow,as shown.

An ore hopper it is positioned to deliver ore onto one end of the oreconveyor. A driven rotary feed valve 4l may be provided in connectionwith the hopper 46 to insure an even feed of ore onto theore conveyorand to prevent the escape of smoke and ley-products of combustionthrough the hopper.

A plurality of xedly mounted rabble arms 48 extend crosswise of theroasting chamber 23 above the ore conveyor and rabble blades 419 on saidrabble arms extend downwardly into the path of the ore on the oreconveyor in suitable positions to stir and agitate the ore on theconveyor as it passes the location of said rabble arms. 'I'he rabblearms are of tubular construction providing for a circulation of airtherethrough to keep said arms from becoming overheated.

The movement of the conveyor is timed so that the ore will be completelyroasted as it is carried from the point of inlet to the discharge end ofthe conveyor. When the ore is discharged from the discharge end of theconveyor it falls through a vertical passageway 5@ onto an inclinedmetal plate or apron 5l which directs said roasted ore downwardlythrough the inclined passageway 25 into the smelting chamber i3. Theapron 5E is of heat resistant material, preferably of cast iron and themajor portion of the space beneath said apron 5l is open so as to afforda free circulation of air in contact with said apron for the purpose ofcooling said apron. A wedge shaped deiector member 52 of metal isprovided to protect the masonry from contact with the falling ores.

The medial furnace section I i is provided with a bottom portion 53,upright walls 54 and an arched top portion 55. An air space 56 isprovided between the arched top po-rtion 55 of the medial furnacesection and the bottom 51 of the upper furnace section. The upperfurnace section has an arched top wall portion 58 above which is a flattop portion 59.

Positioned just in front of the ore inlet hopper 46 is a transversepassageway 69 for by-products of combustion; The walls enclosing thepassageway SQ, preferably extend a short distance above the top of thefurnace, Fig. 1, and said passageway communicates with one or more dustchambers 6l, Fig. 2, at one side of the furnace. The wall 62, Fig. l,between the passageway Gli and the hopper 46 extends downwardly to alocation near the endless traveling ore conveyor leaving just enoughclearance for the ore on the conveyor to pass under the bottom edge ofsaid wall and forming a baffle plate helping to prevent hot gases, smokeand byproducts of combustion from passing outwardly through and aroundthe hopper,

The dust chambers ti are each provided with a convergent lower portion53 through which dust and solid by-products of combustion may passdownwardly to be disposed of in any suit-v able inanner while smoke andgases which can not be caught in these dust chambers pass outwardly andup through a stack til. To direct the heated lay-products of combustiondownwardly in the dust chambers 6i and to assist in the removal, fromthe ley-products of the smelting and roasting furnace, of dust and gaseswhich may carry values or which may be objectlonable if releasedin theatmosphere, I preferably provide in the top portion of each dust chambera deflector wall which extends downwardly into the dust chamber. Also Iprovide means for spraying water into each dust chamber. This spraymeans may consist of water conduits @5 having perforations positioned todirect very nely divided sprays of water across the passageways l2through which the by-products of combustion are traveling in a downwarddirection. Also I make the passageway 12, through which the ley-productstravel downwardly, of smaller size than the passageways 'I3 r throughwhich the ley-products travel upwardly. This accelerates the downwardvelocity of the by-products and helps to deposit the solid particles inthe dust chamber. The water is sprayed under high pressure. This sprayis very nely divided and thoroughly washes the gases which later escapeupthe stack. Also the water spray helps to separate the solid matterfrom the gases by wetting the solid particles and causing them to adheretogether so that they are more liable to drop into the bottom portionsof the dust chambers. Any suitable drain means is provided in the bottomportions of the dust chambers to prevent the accumulation of watertherein. This dust chamber and spray system forms an important partofthis invention as it provides an ecient means for the recovery of valueswhich mightl otherwise escape through the smoke stack and furtherprovides means for cleaning the smoke and by-products of combustion ofobjectionable solid matter and gases. More than two dust chambers 6l maybe provided if desired. i

I find that more heat than is required for the roasting of the ores willoften be traveling upwardly through the passageways that lead from thesmelting chamber i3 to the roasting chamber 23 and for the purpose ofregulating this heat and utilizing said heat to the best advantage Iprovide in they end of the medial section Il two openings t6 and Eil.The opening 66 is connected with a conduit t8 which may lead to anysuitable location where heat which is taken off may be utilized as forinstance to boiler rooms. A damper 69 is provided in the conduit 63 andit will be understood that sufficient draft or suction is present in theconduit 68 to cause a portion of the heated gases to pass outwardlythrough this conduit 68 when the damper 69 is open or partly open. Theopening 61 opens to the atmosphere and functions like a check draft foradmitting cold air to the heated by-products of combustion, said opening61 having a damper 10'by which it may be opened and closed.

In the operation of this continuous process roasting and smeltingfurnace, ore to be'roasted and smelted is fed from the hopper onto theore conveyor and combustion is provided in the smelting chamber I3. Asthe ore is carried toward the discharge end of the conveyor the heatedbyproducts of combustion from the smelting chamber I3, which havetraveled in a generally upward direction through passageways 23, 24 and50, pass over said ore and roast it to the desired extent. The ore isspread out in a relatively thin layer on the ore conveyor and is stirredby the rabble blades as it progresses thus giving the heated gases evenaccess to all of said ore and roasting the same thoroughly in a shortperiod of time. The speed of the ore conveyor may be varied to vary theroasting time for different ores and in proportion to different degreesof heat. The thoroughly roasted ores discharge into the reverberatorysmelting chamber Ai3 where they are reduced to a molten or uid stateproviding for a gravity separation of the gangues from the metals, thuspermitting rst the slag and then the matte to be tapped off in the usualmanner.

From the foregoing description it will be seen that I have provided acontinuous process roasting and smelting furnace which can beconstructed in small sizes at a cost which makes possible itsinstallation at smaller mines; that fI have provided a continuousprocess roasting and smelting'furnace in which the ores pass directlyfrom a roasting chamber into a smelting chamber and in which the excessheat from the smelting chamber is utilized for roasting the ores thusreducing heat losses and costs of ore handling to a minimum. Also byproviding the temperature control chamber between the roasting andsmelting chambers I have provided an efficient means for controlling thetemperature in the roasting chamber. The dust chamber further provides asimple and efficient means for recovering values and removingobjectionable gases which would otherwise escape through the stack.

The foregoing description and accompanying drawings clearly lshow apreferred embodiment of my invention but it will be understoodthat thisdisclosure is merely illustrative and that such changes may be made asare within the spirit and scope of the following claims.

I claim:

1. In a continuous process roasting and smelting furnace; a smeltingchamber; a roasting chamber positioned directly above said smeltingchamber; movable ore supporting means in said roastingchamber positionedto discharge roasted ore from one end portion of said roasting chamberdownwardly into a corresponding end portion of said smelting chamber;and a temperature control chamber positioned between said smeltingchamber and said roasting chamber and communicatively connected with theore discharge end of said roasting chamber and the opposite end of saidsmelting chamber and providing a,

passageway through which heated products of combustion from saidsmelting chamber may pass to said roasting chamber; hot gas take offmeans connected with said temperature control chamber; and cold airinlet means connected with said temperature control chamber, said hotgas take ofi' means and cold air inlet means providing for the controlof the temperature of the gases passing through said temperature controlchamber to said roasting chamber.

2. In a continuous process roasting and smelting furnace, a smeltingchamber; a hydrocarbon burner in said smelting chamber; a roastingchamber positioned directly above said smelting chamber; a temperaturecontrol chamber positioned between said roasting chamber and saidsmelting chamber communicatively connected at one end by a hot gaspassageway with said roasting chamber and at the other end by a hot gaspassageway with said smelting chamber providing conduit means throughwhich hot gases may pass from said smelting chamber to said roastingchamber, said three chambers being substantially horizontal and said hotgas passageways extending in generally upright directions between saidchambers; an endless traveling ore conveyor mounted in said roastingchamber positioned to discharge ore downwardly through the hot gaspassageway which connects said roasting chamber and said temperaturecontrol chamber and across the path of the ascending hot gases; meansforming a conduit between said temperature control chamber and saidsmelting chamber substantially at the bottom of the hot gas passagewayconnecting the roasting chamber with the temperature control chamberthrough which said ore may pass downwardly into said smelting chamber;temperature control means connected with said temperature controlchamber providing for the control of the temperature of gases passingthrough said temperature control chamber to said roasting chamber; andmeans admitting ore into the intake end of said roasting chamber ontosaid traveling conveyor.

3. In a continuous process roasting and smelting furnace, a relativelylong horizontal smelting chamber; heat generating means in said smeltingchamber; a temperature control chamber positioned directly above saidsmelting chamber substantially parallel therewith; passageway means forheated gases connecting one end portion of said temperature controlchamber with the adjacent end portion of said smelting chamber; aninclined deflector plate positioned at the other end portion of saidtemperature control chamber; passageway means for material positioned atthe lower edge of said inclined plate communicating with said smeltingchamber; a roasting chamber positioned directly above said temperaturecontrol chamber substantially parallel therewith; passageway meanscommunicatively connecting the end portion of said temperature controlchamber adjacent said inclined plate with the adjacent end portion ofsaid roasting chamber; ore inlet means positioned at the other endportion of said roasting chamber; ore moving means in said roastingchamber adapted to move ore from said ore inlet through said roastingchamber and discharge the ore onto said inclined plate; and temperaturecontrol means connected with said temperature control chamber.

HANSV WILLIAM JAEGER.

